Over several decades, Hindus (Kashmiri Pandits) were forced to flee the valley by Pakistan backed terrorist and so today you have an artificial majority of Muslims in Kashmir, just as you have in rest of Pakistan.
Looked up the old British surveys. 75% Muslim in the state as a whole from late 1800s right up to just before Independence. I presume you will agree the British had no particular ax to grind in their census.
I am aware of terrorism against Hindus, but that didn’t create the Muslim majority.